This invention relates to a mechanism for transmitting rotational motion from one shaft to another.
Belt or chain drives are generally used to transmit rotational motion from one shaft to another, eg from a crankshaft of an internal combustion engine to a camshaft thereof. However, such drive mechanisms tend to wear and can become noisy. Torque fluctuations also set up vibrations in the chain or belt and this increases wear. Tensioning devices and damper strips are used to alleviate these problems but these complicate the mechanism, reduce its efficiency and can create additional noise. It is also often necessary for the driven shaft to rotate at a precise fraction of the speed of the driving shaft and to maintain a constant phase relationship therewith. Any free-play in the mechanism due to wear or slackness makes it difficult to maintain these relationships.